Integrate rinse module in hybrid bonding platform

ABSTRACT

A method includes performing a plasma activation on a surface of a first package component, removing oxide regions from surfaces of metal pads of the first package component, and performing a pre-bonding to bond the first package component to a second package component.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a divisional of U.S. patent application Ser. No.16/569,019, entitled “Integrate Rinse Module in Hybrid BondingPlatform,” filed on Sep. 12, 2019, which is a divisional of U.S. patentapplication Ser. No. 15/269,346, entitled “Integrate Rinse Module inHybrid Bonding Platform,” filed on Sep. 19, 2016, now U.S. Pat. No.10,665,449 issued May 26, 2020, which is a continuation of U.S. patentapplication Ser. No. 13/888,921, entitled “Integrate Rinse Module inHybrid Bonding Platform,” filed on May 7, 2013, now U.S. Pat. No.9,446,467 issued Sep. 20, 2016, which application claims the benefit ofthe following provisionally filed U.S. patent application: U.S. PatentApplication No. 61/785,993, filed on Mar. 14, 2013, and entitled“Integrated Clean Station in Hybrid Bonding System,” which applicationsare hereby incorporated herein by reference.

BACKGROUND

In wafer-to-wafer bonding technology, various methods have beendeveloped to bond two package components (such as wafers) together. Theavailable bonding methods include fusion bonding, eutectic bonding,direct metal bonding, hybrid bonding, and the like. In the fusionbonding, an oxide surface of a wafer is bonded to an oxide surface or asilicon surface of another wafer. In the eutectic bonding, two eutecticmaterials are placed together, and are applied with a high pressure anda high temperature. The eutectic materials are hence melted. When themelted eutectic materials are solidified, the wafers are bondedtogether. In the direct metal-to-metal bonding, two metal pads arepressed against each other at an elevated temperature, and theinter-diffusion of the metal pads causes the bonding of the metal pads.In the hybrid bonding, the metal pads of two wafers are bonded to eachother through direct metal-to-metal bonding, and an oxide surface of oneof the two wafers is bonded to an oxide surface or a silicon surface ofthe other wafer.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the embodiments, and the advantagesthereof, reference is now made to the following descriptions taken inconjunction with the accompanying drawings, in which:

FIG. 1 illustrates a schematic cross-sectional view of a first packagecomponent that is to be bonded in accordance with some exemplaryembodiments;

FIG. 2 illustrates a schematic cross-sectional view of a second packagecomponent that is to be bonded to the first package component;

FIG. 3 illustrates a cross-sectional view of a plasma activation of thefirst package component;

FIGS. 4 through 6 illustrate an integrated cleaning process including ametal oxide removal and a de-ionized water cleaning process, whichintegrated cleaning process is performed in an integrated cleaningstation;

FIG. 7 illustrates a schematic cross-sectional view of the first packagecomponent after the integrated cleaning process is performed;

FIG. 8 illustrates the cross-sectional view of a pre-bonding process forpre-bonding the first and the second package components; and

FIG. 9 illustrates a process flow for bonding package components and ahybrid bonding system for performing the bonding in accordance withexemplary embodiments.

DETAILED DESCRIPTION

The making and using of the embodiments of the disclosure are discussedin detail below. It should be appreciated, however, that the embodimentsprovide many applicable concepts that can be embodied in a wide varietyof specific contexts. The specific embodiments discussed areillustrative, and do not limit the scope of the disclosure.

A method for bonding package components and the apparatus for performingthe bonding are provided in accordance with various exemplaryembodiments. The intermediate stages of the bonding process areillustrated. The variations of the apparatus and bonding methods inaccordance with embodiments are discussed. Throughout the various viewsand illustrative embodiments, like reference numbers are used todesignate like elements.

FIGS. 1 through 8 illustrate cross-sectional views of intermediatestages in a bonding process in accordance with exemplary embodiments ofthe present disclosure. The process steps may be performed using theintegrated hybrid bonding system 300, which is schematically shown inthe process flow in FIG. 9 . The process flow in accordance with theembodiments is briefly described herein, and the details of the processflow and integrated hybrid bonding system 300 are discussed referring tothe process steps shown in FIGS. 1 through 8 .

Referring to FIG. 9 , the package components that are to be bonded (forexample, package components 100 and 200 in FIGS. 1 and 2 , respectively)are loaded into integrated hybrid bonding system 300 through loadingstation 302. Integrated hybrid bonding system 300 may be located in acontrolled environment, for example, filled with clean air or nitrogen.Alternatively, integrated hybrid bonding system 300 is located in openair. Next, a surface treatment/activation is performed on the surfacesof the package components, wherein the surface treatment is performed insurface treatment station 304. In the surface treatment, the exposedsurfaces of the dielectric materials in the package components areactivated. An integrated cleaning step is then performed on the packagecomponents to remove metal oxides, chemicals, particles, or otherundesirable substances from the surfaces of the package components.Integrated cleaning station 306 is configured to perform the integratedcleaning step in accordance with some embodiments.

A pre-bonding is then performed to bond the package components together.The pre-bonding is performed in pre-bonding station 308. After thepre-bonding, the package components are bonded to each other. The bondedpackage components may then be unloaded from integrated hybrid bondingsystem 300 through unloading station 310, and transferred into annealingstation 312. The bonding strength is then enhanced through a thermalannealing, which is held in thermal annealing station 312.

In the integrated hybrid bonding system 300, a plurality of transferringtools 314 are used to transfer the package components between stations304, 306, and 308, so that stations 304, 306, and 308 may be integratedtogether as an integrated system. Transferring tools 314 may includerobot arms (not shown), transferring guides (not shown), and/or thelike, which are used to automatically transfer the package componentsfrom one station to another, so that the bonding process may beautomated. After the bonding process is finished, the bonded packagecomponents are unloaded from integrated hybrid bonding system 300 usingunloading station 310, which may include robot arms, for example. Inaddition, some or all of stations 304, 306, and 308 and transferringtools 314 may be connected to a central control unit 316, whichcontrols, and coordinates, the operations of stations 304, 306, and 308and transferring tools 314.

A brief hybrid bonding process is discussed herein referring to FIGS. 1through 8 . Referring to FIG. 1 , package component 100 is illustrated.Package component 100 may comprise a device wafer, a package substratestrip, an interposer wafer, or the like. In the embodiments in whichpackage component 100 comprise a device wafer, package component 100 mayinclude semiconductor substrate 102, which may be, for example, asilicon substrate, although other semiconductor substrates are alsousable. Active devices 104 may be formed on a surface of substrate 102,and may include, for example, transistors. Metal lines and vias 106 areformed in dielectric layers 108, which may be low-k dielectric layers insome embodiments. The low-k dielectric layers 108 may have dielectricconstants (k values) lower than about 3.5, lower than about 3.0, orlower than about 2.5, for example. Dielectric layers 108 may alsocomprise non-low-k dielectric materials having dielectric constants (kvalues) greater than 3.9. Metal lines and vias 106 may comprise copper,aluminum, nickel, tungsten, or alloys thereof. Metal lines and vias 106interconnect active devices 104, and may connect active devices 104 tothe overlying metal pads 112.

In alternative embodiments, package component 100 is an interposerwafer, which is free from active devices therein. Package component 100may, or may not, include passive devices (not shown) such as resistors,capacitors, inductors, transformers, and the like in accordance withsome embodiments.

In yet alternative embodiments, package component 100 is a packagesubstrate strip. In some embodiments, package component 100 includeslaminate package substrates, wherein conductive traces 106 (which areschematically illustrated) are embedded in laminate dielectric layers108. In alternative embodiments, package components 100 are build-uppackage substrates, which comprise cores (not shown) and conductivetraces (represented by 106) built on opposite sides of the cores.

In each of the embodiments wherein package component 100 is a devicewafer, an interposer wafer, a package substrate strip, or the like,surface dielectric layer 110 is formed at the surface of packagecomponent 100. In some embodiments, surface dielectric layer 110 is anoxide layer, which may comprise silicon oxide, SiON, SiN, or the like.Metal pads 112 are formed in surface dielectric layer 110, and may beelectrically coupled to active devices 104 through metal lines and vias106. Metal pads 112 may also be formed of copper, aluminum, nickel,tungsten, or alloys thereof. The top surface of surface dielectric layer110 and the top surfaces of metal pads 112 are substantially level witheach other. FIG. 1 also illustrates metal oxides regions 114 formed onthe surfaces of metal pads 112. Metal oxide regions 114 may be thenative oxide regions that are formed due to the exposure of metal pads112 to open air.

In the embodiments wherein package component 100 is a device wafer,surface dielectric layer 110 and metal pads 112, which are used for thesubsequent bonding, may be on the front side (the side with activedevices 104) or the back side of substrate 102, although FIG. 1illustrates that surface dielectric layer 110 and metal pads 112 are onthe front side of substrate 102.

FIG. 2 illustrates package component 200, which is to be bonded topackage component 100. Package component 200 may also be selected from adevice wafer, an interposer wafer, a package substrate, and the like. Inthe illustrated FIG. 2 , package component 200 includes substrate 202,active devices 204, dielectric layers 208, metal lines and vias 206 indielectric layers 208, surface dielectric layer 210, and metal pads 212.Package component 200 may have a structure similar to what is describedfor package component 100, and the details are not repeated herein. Thematerials of the features in package component 200 may be foundreferring to the like features in package component 100, with the likefeatures in package component 100 starting with number “1,” whichfeatures correspond to the features in package component 200 and havingreference numerals starting with number “2.”

Next, referring to FIG. 3 , package component 100 is loaded into surfacetreatment station 304, which is a part of integrated hybrid bondingsystem 300 in FIG. 9 . The loading may be performed using loadingstation 302 as described regarding FIG. 9 . Referring to FIG. 3 , asurface treatment (symbolized by arrows 320) is performed on the surfaceof package component 100. In some embodiments, the surface treatmentincludes a plasma treatment.

The plasma treatment may be performed in a vacuum environment (a vacuumchamber), for example, which is a part of the surface treatment station304 (FIGS. 3 and 9 ). The process gas used for generating the plasma maybe a hydrogen-containing gas, which includes a first combined gas ofhydrogen (H₂) and argon (Ar), a second combined gas of H₂ and nitrogen(N₂), or a third combined gas of H₂ and helium (He). In some exemplaryembodiments, the flow rate ratio of H₂ in the first, the second, or thethird combined gas, whichever is used in the plasma treatment, may bebetween about 4 percent and about 5 percent. Through the treatment, thenumber of OH groups at the surface of surface dielectric layer 110 isincreased, which is beneficial for forming strong fusion bonds.Furthermore, the hydrogen helps reduce the metal oxide 114 on thesurfaces of metal pads 112 back to metal. The plasma treatment may alsobe performed using pure or substantially pure H₂, Ar, or N₂ as theprocess gas, which treats the surfaces of metal pads 112 and surfacedielectric layer 110 through reduction and/or bombardment. The plasmaused in the treatment may be low-power plasma, with the power forgenerating the plasma between about 10 Watts and about 2,000 Watts.Using surface treatment station 304 in FIG. 3 , package component 200 isalso treated, which treatment is essentially the same as the treatmentof package component 100.

Next, referring to FIG. 4 , package component 100 is transferred tointegrated cleaning station 306, and a metal oxide removal and aDe-Ionized (DI) water cleaning are performed on package component 100.The integrated cleaning station 306 includes chamber 402, which may besealed to confine the chemical vapors, which chemical vapors areevaporated from the chemicals used in the cleaning processes that areperformed inside chamber 402. Integrated cleaning station 306 includes aplurality of containers 404, 406, and 408 therein. In some embodiments,the plurality of containers is disposed by placing smaller containersinside lager containers. For example, container 404 is smaller than, andis placed inside, container 406, and container 406 is smaller than, andis placed inside, container 408. Furthermore, the sidewalls of the outercontainers are higher than the sidewalls of the respective innercontainers therein. For example, container 408 has the highestsidewalls, while container 404 has the lowest sidewalls. Containers 404,406, and 408 are connected to outlets 414, 416, and 418, respectively,so that the chemical solutions collected by the containers may beextracted out of chamber 402, and may be collected separately inaccordance with the types of the collected chemical solutions. In someexemplary embodiments, containers 404, 406, and 408 are used to collectused acid solution, used alkaline solution, and used DI water,respectively. In alternative embodiments, the functions of containers404, 406, and 408 may be switched.

Integrated cleaning station 306 also includes a plurality of storages,for example, 424, 426, and 428. The plurality of storages is used tostore the chemicals/solutions that are used in the metal oxide removaland the DI water cleaning. For example, 424, 426, and 428 may store anacidic solution, an alkaline solution, and DI water, respectively.Integrated cleaning station 306 is configured to mix the chemicals andthe DI water, and dispose the chemicals, either mixed or not mixed, tonozzle 430, which is used to dispense the chemical solution to thepackage component (such as package component 100 in FIGS. 5A, 5B, and 6) that is to be cleaned.

Retractable wafer support 432 is located in chamber 402. Retractablewafer support 432 may extend or retract as desired to different levelsduring the integrated cleaning process. Hence, retractable wafer support432 may raise package component 100, as shown in FIG. 6 , or lowerpackage component 100, as shown in FIG. 5B. In some embodiments, airoutlets 434 are disposed in retractable wafer support 432, and are usedto blow air 440 to the back side of package component 100, as will bediscussed referring to FIGS. 5A, 5B, and 6 .

Integrated cleaning station 306 also includes ultrasonic generator 436,which is used to generate ultrasound. The ultrasound is used in thecleaning process, for example, when DI water is disposed on packagecomponent 100. As also shown in FIG. 4 , chamber 402 includes door 438,which is opened to allow package component 100 to be transported intoand out of chamber 402.

Referring to FIG. 5A, after package component 100 is transported intochamber 402, door 438 is closed. During the time period that door 438 isopened, as shown in FIG. 4 , and during the time period door 438 isclosed, as shown in FIGS. 5A, 5B, and 6 , a negative pressure isgenerated in chamber 402, for example, by suck air 439 into chamber 402,and then evacuate the air through an outlet (not shown). With thenegative pressure, which means that the pressure inside chamber 402 islower than the pressure (for example, one atmosphere) outside chamber402, air always flows into, not out of, chamber 402 (except through theoutlet). Hence, the chemical vapors in chamber 402 will not escape topollute the package components and other tools in integrated cleaningstation 306.

FIG. 5A illustrates the metal oxide removal using an alkaline solution,through which oxide regions 114 (FIG. 1 ) are removed. An alkalinesolution such as Ammonium Hydroxide (NH₄OH) solution is disposed onpackage component 100. During the oxide removal, package component 100is rotated to spin off the used alkaline solution. Through the reactionof the alkaline solution with metal oxide regions 114, metal oxideregions 114 are removed. In addition, some loose particles andundesirable substances on the surfaces of metal pads 112 and surfacedielectric layer 110 are also removed. Retractable wafer support 432 mayadjust the height of package component 100 to a level higher than thetop edges of container 404, and lower than the top edges of container406. The alkaline solution spun off from package component 100 may thusbe spun off to the sidewalls of container 406, and evacuated out ofchamber 402 through outlet 416. During the metal oxide removal using thealkaline solution, ultrasonic generator 436 may, or may not, supplyultrasound to package component 100.

FIG. 5B illustrates the metal oxide removal using an acidic solution,through which oxide regions 114 (FIG. 1 ) may also be removed. Duringthe oxide removal, an acidic solution such as formic acid (HCOOH)solution is disposed on package component 100. Package component 100 isrotated to spin off the used acidic solution. Through the use of theacidic solution, the metal oxide regions 114 on the surfaces of metalpads 112 are removed. Some particles and undesirable substances on thesurface of metal pads 112 and surface dielectric layer 110 are alsoremoved. Retractable wafer support 432 may lower package component 100to a level lower than the top edges of container 404. The acidicsolution spun off from package component 100 may thus be spun off to thesidewalls of container 404, and evacuated out of chamber 402 throughoutlet 414. During the metal oxide removal using the acidic solution,ultrasonic generator 436 may, or may not, supply ultrasound to packagecomponent 100.

In accordance with some embodiments, one or both of the alkalinecleaning and/or acid cleaning is performed on package component 100before it is pre-bonded. After the alkaline cleaning and/or the acidcleaning, a DI water cleaning is performed, as shown in FIG. 6 , duringwhich DI water is dispensed on the respective package component 100.Package component 100 is also rotated to spin off the used DI water.Through the use of DI water, the residue of the acidic solution and/orthe alkaline solution is removed. During the DI water clean, retractablewafer support 432 may raise package component 100 to a level higher thanthe top edges of container 406, and lower than the top edges ofcontainer 408. The DI water spun off from package component 100 may thusbe spun off to the sidewalls of container 408, and evacuated out ofchamber 402 through outlet 418. During the cleaning using DI water,ultrasonic generator 436 may, or may not, supply ultrasound to packagecomponent 100.

During the alkaline cleaning, the acid cleaning, and possibly the DIwater cleaning, air, clean air, nitrogen, or other type of gas, whichare represented by arrows 440, may be blown out of outlets 434 (FIGS.5A, 5B, and 6 ). This prevents the acidic solution and the alkalinesolution from flowing to the backside of package component 100 tocontaminate the backside.

Package component 200 is also cleaned using essentially the same processas shown in FIGS. 4 through 6 . After the integrated cleaning, the oxideregions on both package components 100 and 200 are removed. FIG. 7illustrates package component 100, wherein metal pads 112 no longer havemetal oxide regions thereon.

Next, as shown in FIG. 8 , package components 100 and 200 aretransferred into pre-bonding station 308 (also refer to FIG. 9 ).Package components 100 and 200 are aligned, with bond pads 112 ofpackage component 100 being aligned to bond pads 212 of packagecomponent 200. The alignment may be performed in pre-bonding station 308(which is an alignment and pre-bonding station in these embodiments),although it may also be performed in a separate alignment station. Afterthe alignment, package components 100 and 200 are pressed against eachother. At the time the pre-bonding is performed, substantially no oxideis re-grown on the surface of metal pads 112 and 212. This is due to thefact that the oxide regions are removed in the integrated cleaningstation 306, which is a part of the hybrid bonding system. Accordingly,the time period between the removal of the oxide and the pre-bonding isshort enough, and hence substantially no oxide is grown. In addition,the environment of hybrid bonding system 300 (FIG. 9 ) may becontrolled, which includes, for example, using cleaned air or nitrogen(or other inert gases) to fill hybrid bonding system 300, removingmoisture from the air in hybrid bonding system 300, etc. As shown inFIG. 8 , during the pre-bonding, pressing force 326 is applied to presspackage components 100 and 200 against each other. Pressing force 326may be lower than about 5 Newton per die in some exemplary embodiments,although a greater or a smaller force may also be used. The pre-bondingmay be performed at the room temperature (for example, between about 21°C. and about 25° C.), although higher temperatures may be used. Thebonding time may be shorter than about 1 minute, for example.

After the pre-bonding, surface dielectric layer 110 and 210 are bondedto each other. The bonding strength, however, needs to be improved in asubsequent annealing step. The bonded package components 100 and 200 incombination are referred to as bonded pair 324 hereinafter. Bonded pair324 is unloaded out of pre-bonding station 308 and integrated cleaningstation 306 (FIG. 9 ), and is transferred to annealing station 312 (FIG.9 ) for annealing.

Referring to FIG. 9 , in annealing station 312, the bonded pair 324 isannealed at a temperature between about 300° C. and about 400° C., forexample. The annealing may be performed for a period of time betweenabout 1 hour and 2 hours in some exemplary embodiments. When temperaturerises, the OH bonds in oxide layers 110 and 210 (FIG. 8 ) break to formstrong Si—O—Si bonds, and hence package components 100 and 200 arebonded to each other through fusion bonds. In addition, during theannealing, the copper in metal pads 112 and 212 diffuse to each other,so that metal-to-metal bonds are also formed. Hence, the resulting bondsbetween package components 100 and 200 are hybrid bonds.

In the embodiments of the present disclosure, by integrating theintegrated cleaning station into the hybrid bonding system, the oxideson the surfaces of metal bonds are removed. Experiments have shown thatin conventional bonding processes in which the DI water clean isperformed, and no oxide removal is performed in the respective hybridbonding station 300, a resulting bond structure has a clearly visibleinterface, indicating the inferior inter-diffusion of copper atoms. Thebond quality is hence low. As a comparison, by removing the oxide inhybrid bonding system, there is substantially no metal oxide re-grownwhen the bonding is performed. The resulting bond structure has novisible interface, indicating the high-quality inter-diffusion of copperatoms has occurred, and quality of bonds is improved.

In accordance with some embodiments, a method includes performing aplasma activation on a surface of a first package component, removingoxide regions from surfaces of metal pads of the first packagecomponent, and performing a pre-bonding to bond the first packagecomponent to a second package component.

In accordance with other embodiments, a hybrid bonding system includes aplasma treatment chamber configured to perform a plasma cleaning on apackage component, and an integrated cleaning station. The integratedcleaning station includes a chamber, and a plurality of storages outsideof the chamber. The plurality of storages comprises a first storagestoring one of an acidic solution and an alkaline solution therein and asecond storage storing deionized water therein. The integrated cleaningstation further includes a nozzle in the chamber and connected to theplurality of storages, and a retractable wafer support configured tohold the package component thereon. The hybrid bonding system furtherincludes an alignment and pre-bonding station configure to align andbonding the package component with an additional package component.

Although the embodiments and their advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the embodiments as defined by the appended claims. Moreover,the scope of the present application is not intended to be limited tothe particular embodiments of the process, machine, manufacture, andcomposition of matter, means, methods and steps described in thespecification. As one of ordinary skill in the art will readilyappreciate from the disclosure, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed, that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the disclosure.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps. In addition, each claim constitutes a separateembodiment, and the combination of various claims and embodiments arewithin the scope of the disclosure.

What is claimed is:
 1. An apparatus configured to pre-bond a package component, the apparatus comprising: a pre-bonding system comprising: a plasma treatment chamber configured to perform a plasma cleaning process on the package component; an integrated cleaning station comprising: a chamber; a plurality of storages outside of the chamber; a nozzle in the chamber and connected to the plurality of storages; and a retractable wafer support configured to hold the package component thereon; and a first transferring tool configured to transfer the package component from the plasma treatment chamber to the integrated cleaning station.
 2. The apparatus of claim 1 further comprising: an alignment and pre-bonding station connected to the integrated cleaning station, wherein the alignment and the pre-bonding station is configured to align and bond the package component with an additional package component.
 3. The apparatus of claim 2 further comprising a second transferring tool configured to transfer the package component from the integrated cleaning station to the alignment and the pre-bonding station.
 4. The apparatus of claim 1 further comprising: a loading station configured to load the package component into the pre-bonding system; and an unloading station configured to unload the package component out of the pre-bonding system.
 5. The apparatus of claim 1, wherein the retractable wafer support is configured to support the package component at different heights, and rotate the package component at the different heights.
 6. The apparatus of claim 5, wherein the integrated cleaning station further comprises: a first container; and a second container in the first container, wherein the retractable wafer support is in the second container, and is configured to rotate the package component at a first level lower than a first top end of the first container and higher than a second top end of the second container.
 7. The apparatus of claim 6, wherein the retractable wafer support is further configured to rotate the package component at a second level lower than the second top end of the second container.
 8. The apparatus of claim 6, wherein the retractable wafer support is further configured to rotate the package component at a second level higher than the first top end of the first container.
 9. The apparatus of claim 6 further comprising a first outlet and a second outlet connecting bottoms of the first container and the second container, respectively, out of the chamber.
 10. The apparatus of claim 1 further comprising an air outlet in the retractable wafer support, wherein the integrated cleaning station is configured to blow air out of the air outlet toward a back surface of the package component.
 11. An apparatus configured for cleaning a wafer, the apparatus comprising: an integrated cleaning station comprising: a chamber; a first container; and a second container in the first container, wherein a first top edge of the first container is higher than a second top edge of the second container; and a retractable wafer support in the chamber, wherein the retractable wafer support comprises a portion inside the second container, and wherein the retractable wafer support is configured to: rotate the wafer with the wafer being at a first level lower than the second top edge; and rotate the wafer with the wafer being at a second level higher than the second top edge and lower than the first top edge.
 12. The apparatus of claim 11, wherein the retractable wafer support is further configured to rotate the wafer with the wafer being at a third level higher than the first top edge.
 13. The apparatus of claim 11 further comprising a nozzle in the chamber, wherein the integrated cleaning station is configured to dispense a chemical on the wafer through the nozzle at a time the wafer is rotated by the retractable wafer support.
 14. The apparatus of claim 11 further comprising: a first outlet connecting a first bottom of the first container out of the chamber; and a second outlet connecting a second bottom of the second container out of the chamber.
 15. The apparatus of claim 14 further comprising: a third container, with the first container and the second container in the third container; and a third outlet connecting a third bottom end of the third container out of the chamber.
 16. An apparatus configured for cleaning a wafer, the apparatus comprising: a chamber; a first container comprising a first sidewall having a first height; a second container in the first container, wherein the second container comprises a second sidewall having a second height lower than the first height; a third container in the second container, wherein the third container comprises a third sidewall having a third height lower than the second height; and a retractable wafer support in the chamber and having a top end, wherein the retractable wafer support is configured to have the top end adjusted to a plurality of levels, and is configured rotate when its top end is at each of the plurality of levels.
 17. The apparatus of claim 16, wherein the retractable wafer support comprises air outlets at a position lower than the top end of the retractable wafer support.
 18. The apparatus of claim 16, wherein the first container, the second container, and the third container comprise outlets leading out of the chamber.
 19. The apparatus of claim 18, wherein each of the first container, the second container, and the third container comprises an outlet leading out of the chamber.
 20. The apparatus of claim 16, wherein the chamber is sealable. 